Active agent elution control coatings are now commonly used to deliver active agents to tissues of the body. Elution control coatings can enable the delivery of an active agent over a period of time in order to optimize therapeutic effect. In addition, when disposed on a medical device, elution control coatings can enable site-specific active agent delivery because the medical device can be positioned as desired within the body of a patient.
A desirable elution rate for an active agent in one treatment scenario may be different than a desirable elution rate for an active agent in another treatment scenario. Therefore, it can be advantageous to be able to manipulate or change the elution kinetics of a coating in order to more closely match what is desirable for a specific treatment scenario.
Active agents delivered from elution control coatings can include many different types of compounds including small hydrophilic molecules, small hydrophobic molecules, macromolecules such as carbohydrates, peptides, proteins, and the like. Of these compounds, peptides and proteins can pose a challenge because, in general, they are susceptible to denaturation. In addition, the unique properties of peptides and proteins, such as their relatively large size, can frequently result in them being delivered either more quickly or more slowly than desired.
Accordingly, there is a need for coatings that can deliver active agents at desirable rates and methods of making the same. There is also a need for coatings that can be used to control the elution rate of macromolecules such as peptides and proteins.